This project will test the hypothesis that the representations of planning and execution of 3-D reaching movements by primates are widely distributed across multiple cortical areas, although the relative contribution of each area will differ depending upon whether visual stimuli are present. The hypothesis will be tested by recording the concurrent activity of large numbers of single neurons (up to 100) in the dorsolateral prefrontal; dorsal premotor, primary motor, and posterior parietal (area 7) cortices of monkeys. By comparing movement-related neuronal activity across behavioral conditions in which the presence of visual stimuli are varied during both the planning and execution stages, this project will characterize how visual stimuli influence the processing of planning and movement across cortical areas. In addition, the study will determine the extent to which reach planning and execution are represented by interactions between neurons across multiple cortical areas. This project will provide information that is critical for understanding how reach planning and execution are represented in multiple cortical areas simultaneously, and in particular, how visuomotor processing is carried out by these cortical areas.